Android6.0 创建TYPE_SYSTEM_ALERT级别的弹出框方法

原文：http://www.enjoydiy.com/3554.html
突然发现在android6之前的版本都是可以弹出系统级别的dialog, 但是到了6.0就不行了, 搜索发现官方文档有下面说明:

Allows an app to create windows using the type TYPE_SYSTEM_ALERT, shown on top of all other apps. Very few apps should use this permission; these windows are intended for system-level interaction with the user.

Note: If the app targets API level 23 or higher, the app user must explicitly grant this permission to the app through a permission management screen. The app requests the user’s approval by sending an intent with action ACTION_MANAGE_OVERLAY_PERMISSION. The app can check whether it has this authorization by calling Settings.canDrawOverlays().

Protection level: signature

Constant Value: “android.permission.SYSTEM_ALERT_WINDOW”

首先检查下有没有权限绘出系统的级别的对话框, 有可以直接画出, 没有的话需要发个intent让用户授权, 具体实现代码如下:
if (Build.VERSION.SDK_INT >= 23) {
if(!Settings.canDrawOverlays(this)) {
Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION);
startActivity(intent);
return;
} else {
//绘ui代码, 这里说明6.0系统已经有权限了
}
} else {
//绘ui代码,这里android6.0以下的系统直接绘出即可
}